package com.sntk.registermanager.common.utils;

import javax.servlet.http.HttpServletRequest;
import java.io.UnsupportedEncodingException;
import java.util.StringTokenizer;

/**
 * @ClassName: IPUtil
 * @author: wgchao
 * @createTime: 2020/9/14 9:43 AM
 * @Description: TODO
 */
public class IPUtil {

    private static StringBuilder sb = new StringBuilder();

    /**
     * 获取登录用户的IP地址
     *
     * @param request
     * @return
     */
    public static String getIpAddr(HttpServletRequest request) {
        String ip = request.getHeader("x-forwarded-for");
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("Proxy-Client-IP");
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("WL-Proxy-Client-IP");
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getRemoteAddr();
        }
        if ("0:0:0:0:0:0:0:1".equals(ip)) {
            ip = "127.0.0.1";
        }
        if (ip.split(",").length > 1) {
            ip = ip.split(",")[0];
        }
        return ip;
    }


    /**
     * 从ip的字符串形式得到字节数组形式
     *
     * @param ip
     * 字符串形式的ip
     * @return 字节数组形式的ip
     */
    public static byte[] getIpByteArrayFromString(String ip) {
        byte[] ret = new byte[4];
        StringTokenizer st = new StringTokenizer(ip, ".");
        try {
            ret[0] = (byte) (Integer.parseInt(st.nextToken()) & 0xFF);
            ret[1] = (byte) (Integer.parseInt(st.nextToken()) & 0xFF);
            ret[2] = (byte) (Integer.parseInt(st.nextToken()) & 0xFF);
            ret[3] = (byte) (Integer.parseInt(st.nextToken()) & 0xFF);
        } catch (Exception e) {
            System.out.println("从ip的字符串形式得到字节数组形式报错");
        }
        return ret;
    }
    /**
     * @param ip
     * ip的字节数组形式
     * @return 字符串形式的ip
     */
    public static String getIpStringFromBytes(byte[] ip) {
        sb.delete(0, sb.length());
        sb.append(ip[0] & 0xFF);
        sb.append('.');
        sb.append(ip[1] & 0xFF);
        sb.append('.');
        sb.append(ip[2] & 0xFF);
        sb.append('.');
        sb.append(ip[3] & 0xFF);
        return sb.toString();
    }
    /**
     * 根据某种编码方式将字节数组转换成字符串
     *
     * @param b
     * 字节数组
     * @param offset
     * 要转换的起始位置
     * @param len
     * 要转换的长度
     * @param encoding
     * 编码方式
     * @return 如果encoding不支持，返回一个缺省编码的字符串
     */
    public static String getString(byte[] b, int offset, int len,
                                   String encoding) {
        try {
            return new String(b, offset, len, encoding);
        } catch (UnsupportedEncodingException e) {
            return new String(b, offset, len);
        }
    }

    /**
     * 对用户ip格式化
     * @param request
     * @return
     */
    public static String encodeIp(HttpServletRequest request){
        String ip = getIpAddr(request);
        byte[] bip = getIpByteArrayFromString(ip);
        return getString(bip, 1, bip.length, null);
    }
}
